7. Project Summary/Abstract Adolescence is a critical window of neuroplasticity when environmental inputs such as parenting can have a significant impact on adolescent behavior and the ability to self-regulate, yet research on the role of parenting behaviors has been limited to early-childhood effects. Although some studies have documented effects of adolescent-specific parenting on self-regulation and externalizing behaviors, no study to date has used a national longitudinal sample to examine these developmental linkages in a systematic manner from early childhood to adolescence. As such, it remains unclear whether parenting effects on externalizing behaviors and underlying self-regulatory abilities are enduring (i.e., carried forward from younger years), or if unique adolescent-specific effects are in play. Further, what are the underlying mechanisms by which parenting behaviors affect child externalizing behaviors across development? To address these questions, the proposed study will use existing longitudinal data from the NICHD Study of Early Child Care and Youth Development (SECCYD) to (a) examine the transactional linkages between three parenting behaviors and child executive functions, self-regulation, and externalizing behaviors from early childhood to adolescence by using separate bivariate transactional models for each parenting behavior and child outcome combination; and (b) assess the mediating roles of child executive functions and self-regulation in the mechanistic pathway by which parenting behaviors affect child externalizing behaviors from early childhood to adolescence. By identifying whether parenting behaviors can exert unique adolescent-specific effects and delineating the mechanisms of influence of parenting behaviors across development, the proposed study will advance current understanding of parenting effects and facilitate the development of more-targeted parenting-based interventions beyond early childhood. Findings from the this study will inform the design of future longitudinal studies with socioeconomically and ethnically diverse samples to explore variations in parenting effects based on sociodemographic and contextual factors, and use of twin or adoption study designs to disentangle genetic and environmental effects.